Tank-type flush toilets, in which flushwater supplied from a water main is collected in a flushwater tank, and a bowl section is cleaned by flushing with the flushwater in the tank, are widely used. In flush toilets of this type, in which the bowl section is cleaned by causing flushwater to be expelled from a rim section in the upper part of the bowl section and a jet hole, flushwater in the flushwater tank is divided and supplied to the rim section and to the jet hole. That is, when a drain valve disposed on the bottom portion of the flushwater tank is opened by a flushing operation, flushwater flows into a supply chamber formed on the main body of the flush toilet. The supply water chamber communicates with a rim water conduit and a jet water conduit; flushwater which has flowed into the supply water chamber branches and flows to the rim water conduit and the jet water conduit, supplying water to the rim and to the jet.
However, water conduits for supplying flushwater are complicated in flush toilets in which flushwater from a flushwater tank is caused to branch when being supplied, thus increasing flow path resistance in the water conduit. It is therefore necessary to make the water level of the flushwater stored in the flushwater tank sufficiently high that expelling of flushwater from the jet hole can be accomplished with sufficient water flow even if a loss of pressure in the water conduit occurs. “Low silhouette” type flush toilets are therefore difficult to implement in flush toilets of this type. In the present Specification, flush toilets in which the top surface of the tank is less than approximately 200 mm from the top surface of the rim section are referred to as low silhouette-type flush toilets.
A flush toilet comprising a water supply structure furnished with a jet drain valve for supplying water to a jet hole and a rim drain valve for supplying water to a rim section is set forth in Japanese Unexamined Patent Application Publication No. H7-180202 (Patent Ref. 1). In this toilet, the water conduit is simplified and water conduit fluid resistance is reduced by providing separate jet and rim drain valves.
Patent Reference 1: Unexamined Patent Application Publication No. H07-180202.